In financial transactions involving a payment card (e.g., a credit card), purchaser authorization is typically provided via the same channel through which the account number is provided. For example, this may be in the form of a PIN or a signature at a point-of-sale terminal. Even in technologies that allow for a greater amount of security, i.e., where the payment processing network separately initiates a purchaser authorization exchange (e.g., Verified by Visa®, or MasterCard® SecureCode), purchaser authorization is also provided via the same channel through which the account number is provided (i.e., an internet browser).